Lieut. Nelson on the Geology of the Bermudas. Ill 



tained in stone which has acquired great hardness. On the beach, about 300 yards west of Rose- 

 lands, the matrix was so firmly attached to slabs of sound, compact, sonorous limestone, as to be in 

 many instances perfectly identified with them. It cost me nearly as much labour to dislodge 

 some of these specimens as I have bestowed on greenstones. An Astrea, like A. Rotulosa, Turbo 

 Pica, fragments of Ostrea, Spondylus, &c. &c., all contributed with the shelly sand towards the 

 formation of this striking conglomerate. 



Other blocks of coral reef may be found, imbedded in the rock on the south side. There is one 

 in particular 300 yards east of Elbow Bay, about ten yards from the water's edge, and four or five 

 feet above it; at some points this block is quite assimilated with the matrix, but at others, stands 

 out in relief, in consequence of its greater durability. 



The calcareous tubes are very generally found throughout the islands, apparently aggregated 

 around grass or small roots, as nuclei, which have subsequently decayed. They have almost always 

 an earthy matter running down the axis. Beds, nay strata of these tubular deposits, may be found 

 in various parts, as in the neighbourhood of Tobacco Bay near St. George's, and in the bank a 

 little to the westward of Harris's Bay, where the cliffs commence ; though nowhere to such an 

 extent as at Ireland Island, between Bombay and the south-west point, where the stratum is 

 about four feet thick, and corresponds to a similar formation on Skinner's or Tate's Island. 



The cliffs to the westward of Elbow Bay are curiously perforated to a great extent by similar 

 tubular holes ; but there they are detached from each other, and are generally vertical and much 

 larger. 



Organics. 



The whole of the Bermudas, and perhaps many of the older rocks, may 

 be called " Organic Formations/' as they present but one mass of animal re- 

 mains, in various stages of comminution and disintegration. From the most 

 compact rock to the very sand of the shore, the materials are universally frag- 

 ments of shells, corals, &c. &c. Of the former the Venus Pennsylvanica 

 is the most abinidant, being found in every part of the colony, more especially 

 among the newer aggregates on the coast; and in every stale, from the 

 perfect specimen to the smallest particle. A stratum of these, in indifferent 

 preservation, is in the quarry whence the stone for the pier at St. George's 

 ferry was obtained. This bed, however, is of trifling extent compared with 

 an apparently corresponding one in the chain of islets reaching across the 

 mouth of Crow-lane Harbour, beginning near Phyllis' Island, and continuing 

 thence through every point in the line till it reaches Harris's Island : it is 

 about five feet thick and lies about six feet above the water. 



In the chain above-mentioned I have obtained excellent specimens of the 

 Scutella Quinqueforis , having the pores of the crust filled with crystallized 

 carbonate of lime ; like the Echinites occasionally found similarly circum- 

 stanced in the European chalk. 



The Turbo Pica is very abundant, with the nacre and colours ; but like 

 the Venus Pennsylvanica, it is chiefly met with in sand-pits, and more recent 

 formations, though without the slightest reference to the hardness of the 



